Poly(bromoaryl)alkane additives and methods for their preparation and use

ABSTRACT

An additive mixture useful as a flame retardant is described. The mixture is comprised of (i) a poly(bromophenyl)alkane having in the molecule in the range of 13 to 60 carbon atoms and in the range of two to four aryl groups and (ii) a poly(bromophenyl)bromoalkane having in the molecule in the range of 13 to 60 carbon atoms and in the range of two to four aryl groups, said poly(bromophenyl)bromoalkane being in an amount which is greater than 25 wt %, based on the total weight of the additive mixture. A facile process for making the poly(bromophenyl)bromoalkane is also described.

REFERENCE TO RELATED APPLICATION

The benefit of the filing date priority of U.S. Provisional Patent Appl.No. 60/309,810, filed on Aug. 3, 2001, is hereby claimed.

BACKGROUND

Polyhalogenated diarylalkanes, e.g. decabromodiphenylethane, are knownflame retardants for use in polyolefin and polystyrenic-basedformulations. On a commercial basis, the polyhalogenated diarylalkane issupplied to the formulation as a product predominant in thepolyhalogenated diarylalkane selected. Heretofore, known formulations ofpolyhalogenated diarylalkanes were brominated at the aryl rings(s)exclusively. Thus, such formulations were thus less desirable when thecircumstance of use of the flame retardant called for the beneficialaspects of an aliphatically brominated composition.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a differential scanning calorimetry curve of deca- anddodecabromodiphenylethane.

Thus, a need exists for a flame retardant formulation which combines thebeneficial characteristics of flame retardants having aryl group brominesubstitution and flame retardants having aliphatic bromine substitution.

THE INVENTION

This invention meets this need by providing, inter alia, an additivemixture comprised of (i) a poly(bromoaryl)alkane and (ii) apoly(bromoaryl)bromoalkane. The alkane bridge of thepoly(bromoaryl)bromoalkane has at least one bromine atom substituent,and preferably has at least one bromine atom substituent on each carbonatom of the bridge. Although not required, the aryl groups of bothcomponents (i) and (ii) are preferably perbrominated. Additives of thisinvention exhibit surprisingly beneficial fire retardantcharacteristics, and macromolecular formulations which include theseadditives having surprisingly beneficial physical properties.

In one embodiment of this invention, an additive mixture comprises (i) apoly(bromoaryl)alkane having in the molecule in the range of 13 to 60carbon atoms and in the range of two to four aryl groups and (ii) apoly(bromoaryl)bromoalkane having in the molecule in the range of 13 to60 carbon atoms and in the range of two to four aryl groups, wherein atleast one of the aryl groups of each of (i) and (ii) has at least 7carbon atoms. The alkane bridge of the poly(bromoaryl)bromoalkanepreferably will have at least two carbon atoms in the bridge and atleast two bromine atom substituents on the bridge, and even morepreferably will have at least two carbon atoms in the bridge and anumber of bromine substituents on the bridge equal to the number ofcarbon atoms in the bridge. Preferably, the poly(bromoaryl)bromoalkaneis present in an amount which is greater than 10 wt %, and morepreferably greater than 20 wt %, and most preferably greater than 25 wt%, based on the total weight of the additive mixture.

In another embodiment of this invention, an additive mixture comprises(i) a poly(bromoaryl)alkane having in the molecule in the range of 13 to60 carbon atoms and in the range of two to four aryl groups, themolecule having less than complete bromination of the available arylgroup substitution sites, (ii) a poly(perbromoaryl)alkane having in themolecule in the range of 13 to 60 carbon atoms and in the range of twoto four aryl groups, and (iii) a poly(perbromoaryl)bromoalkane having inthe molecule in the range of 13 to 60 carbon atoms and in the range oftwo to four aryl groups, wherein at least one of the aryl groups of eachof (i) and (ii) has at least 7 carbon atoms. The alkane bridge of thepoly(bromoaryl)bromoalkane preferably will have at least two carbonatoms in the bridge and at least two bromine atom substituents on thebridge, and even more preferably will have at least two carbon atoms inthe bridge and a number of bromine substituents on the bridge equal tothe number of carbon atoms in the bridge. Preferably, thepoly(bromoaryl)bromoalkane is present in an amount which is greater than10 wt %, and more preferably greater than 20 wt %, and most preferablygreater than 25 wt %, based on the total weight of the additive mixture.

In a preferred embodiment of this invention, an additive mixturecomprises (i) a poly(bromophenyl)alkane having in the molecule in therange of 13 to 60 carbon atoms and in the range of two to four phenylgroups and (ii) a poly(bromophenyl)bromoalkane having in the molecule inthe range of 13 to 60 carbon atoms and in the range of two to fourphenyl groups, said poly(bromophenyl)bromoalkane being in an amountwhich is greater than 20 wt %, based on the total weight of the additivemixture, and more preferably being in an amount which is greater than 25wt %, based on the total weight of the additive mixture. The alkanebridge of the poly(bromoaryl)bromoalkane preferably will have at leasttwo carbon atoms in the bridge and at least two bromine atomsubstituents on the bridge, and even more preferably will have at leasttwo carbon atoms in the bridge and a number of bromine substituents onthe bridge equal to the number of carbon atoms in the bridge.

The poly(bromoaryl)alkane in additives of this invention preferably hasin the range of 13 to about 24 carbon atoms, and the alkane portion ofthe molecule preferably has in the range of 1 to about 10 carbon atoms,more preferably in the range of 2 to about 10 carbon atoms, and mostpreferably in the range of 2 to about 6 carbon atoms. When the alkanecontains 2 or more carbon atoms, it is preferred that at least eachterminal carbon atom is aryl substituted. Di(bromoaryl)alkanes are apreferred species. The brominated aryl groups are homocyclic, and mayhave alkyl substituents or oxygen or nitrogen-containing substitutents,e.g., —OH or —NH₂. The aryl groups each have at least one brominesubstituent, preferably having two or more bromine substituents, andmore preferably being perbrominated. Alkyl substituents on the arylring, if present, have in the range of one to about four carbon atoms,and most preferably one carbon atom. Preferred aryl groups are naphthyland phenyl, with phenyl being particularly preferred. Examples of othersuitable aryl groups that may be used include tolyl, xylyl,isopropylphenyl, naphthyl, 6-ethylnaphthyl, anthryl, phenanthryl,chrysyl, pyrenyl, and 9,10-benzophenanthryl. It is preferred that allaryl groups of the molecule be the same. Examples of suitablepoly(perbromoaryl)alkanes include decabromodiphenylmethane,dodecabromodi(6-ethylnaphthyl)methane, decabromo-1,1-diphenylethane,pentadecabromotriphenylethane, tetradecabromo-1,2-dinaphthylethane,dodecabromo-1-naphthyl-2-phenylethane, decabromo-1,2-diphenylpropane,decabromo-2,2-diphenylpropane, decabromo-1,3-diphenylpropane,pentadecabromo-1,2,3-triphenylpropane, decabromo-1,4-diphenylbutane,octadecabromo-1,3-dianthrylbutane,decabromo-2,3-dimethyl-1,4-diphenylbutane,decabromo-2-ethyl-3-methyl-1,4-diphenylbutane,nonabromo-1-phenyl-5-tolylpentane, decabromo-1,5-diphenylhexane,octadecabromo-1,6-diphenanthrylhexane,decabromo-2-methyl-1,6diphenylhexane,hexadecabromo-2-naphthyl-6-pyrenylheptane,octabromo-1,8-di(tolyl)octane, hexabromo-1,9-di(xylyl)nonane,octacosabromo-1,4,6,9-tetranaphthylnonane,tetradecabromo-1,10-dinaphthyldecane,eicosabromo-1,1,10,10-tetraphenyldecane, and the like, including loweraryl-brominated analogs, i.e., analogs wherein the number of brominesubstituents on the aryl groups is less than the number of carbon atomsin the aryl groups eligible for bromine substitution.Decabromodiphenylmethane and decabromo-1,2-diphenylethane are highlypreferred poly(perbromoaryl)alkanes.

The poly(bromoaryl)bromoalkane of additives of this invention are asdescribed above for the poly(bromoaryl)alkanes, but are furtherbrominated by substitution of at least one bromine atom on the alkanebridge, and more preferably at least one bromine atom on each of thecarbon atoms in the alkane bridge. Higher levels of bromination of thecarbon atoms in the alkane bridge are also envisioned by, and are withinthe scope of, this invention, as long as thermal and UV stability forthe application at hand are not significantly adversely affected by suchadditional bromination. Examples of suitablepoly(perbromoaryl)bromoalkanes in which one or more carbon atoms of thealkane bridge is bromine-substituted thus includeundecabromodiphenylmethane, tridecabromodi(6-ethylnaphthyl)methane,undecabromo-1,1-diphenylethane, hexadecabromotriphenylethane,pentadecabromo-1,2-dinaphthylethane, hexadecabromo-1,2-dinaphthylethane,tridecabromo-1-naphthyl-2-phenylethane,tetradecabromo-1-naphthyl-2-phenylethane,undecabromo-1,2-diphenylpropane, dodecabromo-1,2-diphenylpropane,tridecabromo-1,2-diphenylpropane, undecabromo-2,2-diphenylpropane,dodecabromo-2,2-diphenylpropane, tridecabromo-2,2-diphenylpropane,undecabromo-1,3-diphenylpropane, dodecabromo-1,3-diphenylpropane,tridecabromo-1,3-diphenylpropane, hexadecabromo-1,2,3-triphenylpropane,heptadecabromo-1,2,3-triphenylpropane,octadecabromo-1,2,3-triphenylpropane, undecabromo-1,4-diphenylbutane,dodecabromo-1,4-diphenylbutane, tridecabromo-1,4-diphenylbutane,tetradecabromo-1,4-diphenylbutane, nonadecabromo-1,3-dianthrylbutane,undecabromo-2,3-dimethyl-1,4-diphenylbutane,undecabromo-2-ethyl-3-methyl-1,4-diphenylbutane,decabromo-1-phenyl-5-tolylpentane, undecabromo-1,5-diphenylhexane,nonadecabromo-1,6-diphenanthrylhexane,undecabromo-2-methyl-1,6-diphenylhexane,heptadecabromo-2-naphthyl-6-pyrenylheptane,nonabromo-1,8-di(tolyl)octane, heptabromo-1,9-di(xylyl)nonane,nonacosabromo-1,4,6,9-tetranaphthylnonane,pentadecabromo-1,10-dinaphthyldecane,heneicosabromo-1,1,10,10-tetraphenyldecane, and the like, includinghigher and lower aliphatically brominated analogs and loweraryl-brominated analogs. Undecabromodiphenylmethane anddodecabromo-1,2-diphenylethane are highly preferredpoly(perbromoaryl)bromoalkanes. In this context, the terms higher andlower are meant to refer to analogs wherein the number of brominesubstituents on the aryl groups or alkane bridge, as the case may be, ismore (higher) or less (lower).

The additives of this invention may be fabricated using a variety ofmethods. Of course, components of the additives may be separatelyfabricated using different processes and subsequently mixed together toform the additives, or a fabrication process may be adapted to permitthe formation of additives of this invention in a single process.Regardless of the method chosen, the additive must be formed so as tocontain at least one poly(bromoaryl)bromoalkane, wherein the alkanebridge is substituted with at least one bromine atom, and preferably atleast two bromine atoms, more preferably at least one bromine atom ateach carbon atom in the bridge. Exemplary methods of fabrication ofpoly(bromoaryl)alkanes are taught, e.g., in commonly owned U.S. Pat.Nos. 5,008,477, 5,030,778, 5,077,334, 5,124,496, 5,302,768, 5,324,874and 5,401,890, the entire disclosures of which are incorporated hereinby reference. The poly(bromoaryl)alkane produced in accordance with aknown method may be further brominated at the alkane bridge through analiphatic bromination step in the presence of a brominating agent,either in the form of entrained bromine or in the form of a brominatingagent which has been brought into contact with thepoly(bromoaryl)alkane. Examples of suitable brominating agents includeelemental bromine (either in liquid or vapor form), N-bromosuccinimide,an organic brominating agent such as 1,3-dibromodimethylhydantoin, andthe like, with elemental bromine being preferred since additionalpurification steps may be required when using other brominating agents.Such aliphatic bromination may be carried out using, e.g., one of thefree radical bromination processes such as photochemical bromination,thermal bromination, peroxide or azo compound bromination. Because ofthe highly corrosive conditions and pressure requirements, thermalbromination will in some situations be less preferred to photochemicalbromination or the reactions in which peroxides or other suitable areused.

In photochemical bromination, the poly(bromoaryl)alkane is placed in thepresence of a brominating agent and a solvent which is able to at leastpartially dissolve the poly(bromoaryl)alkane under the reactionconditions, and the mixture is exposed to a sufficient type and amountof light to cause the brominating agent to cleave to form a bromine atomwhich reacts with the poly(bromoaryl)alkane, and specifically with ahydrogen atom at the alkane bridge of the poly(bromoaryl)alkane. Thelight employed may be any light as long as it is of sufficient strengthto cause the reaction to occur. The reaction conditions are nottemperature dependent, as long as at least a portion of the reagentsremain in solution during the process. Maintaining an elevatedtemperature during the process is also not critical, but it can assistthe reaction speed if some elevated temperature, i.e., a temperatureabove 25° C., is employed. Adding pressure to the conditions can alsospeed up the reaction time, although the reaction can conceivably beconducted at subatmospheric, atmospheric, and super atmosphericpressure. Maintaining substantially anhydrous conditions during theprocess is preferred, as is the use of an inert atmosphere such as,e.g., nitrogen or argon.

In thermal bromination, the poly(bromoaryl)alkane is heat treated to atemperature of at least 250° C., and more preferably to at least 300°C., under substantially closed reactor conditions to prevent release ofbromine in the form of, e.g., HBr, to effectuate a thermal brominationof at least one or more of the carbon atoms in the alkane bridge.Typically, a maximum temperature for poly(aryl)alkane thermalbromination will be about 350° C. Generally speaking, the longer thethermal bromination is conducted, the more bromination will occur at theavailable sites of the alkane bridge. The thermal bromination is carriedout for a period of time the length of which will vary depending uponthe desired level of aliphatic bromination, the startingpoly(bromoaryl)alkane and the surrounding reaction conditions. Theamount of poly(bromoaryl)bromoalkane which is formed from thepoly(bromoaryl)alkane product will be affected by the amount ofavailable brominating agent and the level and duration of heat appliedto the reaction mass. Generally speaking, in the case of thermalbromination of a decabromodiphenylethane mixture having a minor (e.g., 5wt %) amount of dodecabromodiphenylethane, the time necessary to convertthe mixture to one having at least 25 wt % dodecabromodiphenylethanewill be in the range of about 1 to about 6 hours, more preferably about2 to about 4 hours, when the temperature is maintained at about 300° C.Preferably, the amount of brominating agent and heat applied, and theduration of the bromination process will be selected to convertpoly(bromoaryl)alkane to a a mixture of poly(bromoaryl)alkane and asignificant amount of poly(bromoaryl)bromoalkane. By significant amountit is meant that at least about 5 wt %, preferably at least about 20 wt% and more preferable at least about 25 wt %, by weight of the resultingproduct, is present. When the poly(bromoaryl)alkane to be heat-treatedis decabromodiphenylethane, the preferred amount ofdodecabromodiphenylethane produced is greater than 20 wt % and morepreferably greater than 25 wt %, based upon the total weight of the endproduct. To form this amount of dodecabromodiphenylethane, excessbrominating agent (relative to decabromodiphenylethane) typically willbe required. As an alternative to the previously mentioned processes forbromination of a poly(bromoaryl)alkane, additives of this invention mayalso be produced by simply mixing together a previously fabricatedpoly(bromoaryl)alkane and a previously fabricatedpoly(bromoaryl)bromoalkane, so as to form an additive of this invention.

Additives in accordance with this invention are surprisingly stable andhave favorable morphology characteristics. The additive composition ofthis invention may be used as a flame retardant in formulation withvirtually any flammable material. The material may be macromolecular,for example, a cellulosic material or a polymer. Illustrative polymersare: olefin polymers, cross-linked and otherwise, for example,homopolymers of ethylene, propylene, and butylene; copolymers of one ormore of such alkylene monomers and any other copolymerizable monomers,for example, ethylene/propylene copolymers, ethylene/ethyl acrylatecopolymers and ethylene/vinyl acetate copolymers; polymers ofolefinically unsaturated monomers, for example, polystyrene, e.g., highimpact polystyrene, and styrene copolymers; polyurethanes; polyamides;polyimides; polycarbonates; polyethers; acrylic resins; polyesters,especially poly(ethyleneterephthalate) and poly(butyleneterephthalate);epoxy resins; alkyls; phenolics; elastomers, for example,butadiene/styrene copolymers and butadiene/acrylonitrile copolymers;terpolymers of acrylonitrile, butadiene and styrene; natural rubber;butyl rubber, and polysiloxanes. The polymer may also be a blend ofvarious polymers. Further, the polymer may be, where appropriate,cross-linked by chemical means or by irradiation. Other preferredsubstrate or host polymers include the following:

a) Thermoplastic polyesters, such as polyethylene terephthalate, andespecially one or more of such thermoplastic polyesters as polypropyleneterephthalate, polybutylene terephthalate, polycyclohexylene dimethyleneterephthalate, and related copolyesters and blends, including blends ofone or more thermoplastic polyesters with one or more otherthermoplastic polymers such as polycarbonates, and especially aromaticpolycarbonates.

b) Glass-reinforced thermoplastic polyesters, such as polyethyleneterephthalate, and especially one or more of such glass-reinforcedthermoplastic polyesters as polypropylene terephthalate, polybutyleneterephthalate, polycyclohexylene dimethylene terephthalate, and relatedcopolyesters and blends, including blends of one or more thermoplasticpolyesters with one or more other thermoplastic polymers such aspolycarbonates, and especially aromatic polycarbonates.

c) Thermoplastic polyamides, especially one or more of suchthermoplastic polyamides such as nylon 6, nylon 6,6, nylon 6,9, nylon6,10, nylon 6,12, nylon 11, nylon 12, nylon 12,12, nylon 6/6,6copolymer, and high temperature nylons such as nylon 4,6, and partiallyaromatic nylons (e.g., Ixef polyarylamide PA MXD6 from Solvay, Zytel HTNfrom DuPont, and Amodel polyarylamide from Amoco). Other polyamideswhich may be used include Stanyl polyamide 46 from DSM, Vydyne polyamide6/66 copolymers from Monsanto, polyamide 612 (Vestamid D from Creanova),and similar polyamides. Of the various nylon polymers, nylon 6 and nylon6,6 are the preferred substrate polymers.

d) Glass-reinforced thermoplastic polyamides, especially one or more ofsuch glass-reinforced thermoplastic polyamides as glass-reinforced nylon6, nylon 6,6, nylon 6,9, nylon 6,10, nylon 6,12, nylon 11, nylon 12,nylon 12,12, nylon 6/6,6 copolymer, or glass-reinforced high temperaturenylons such as nylon 4,6, and partially aromatic nylons (e.g., Ixefpolyarylamide PA MXD6 from Solvay, Zytel HTN from DuPont, and Amodelpolyarylamide from Amoco). Other glass-reinforced polyamides which maybe used include glass-reinforced Stanyl polyamide 46 from DSM, Vydynepolyamide 6/66 copolymers from Monsanto, polyamide 612 (Vestamid D fromCreanova), and similar polyamides. Of the various glass-reinforced nylonpolymers, those of nylon 6 and nylon 6,6 are the preferred substratepolymers.

e) Vinylaromatic polymers such as polystyrene, andpoly(alpha-methylstyrene), and copolymers of two or more styrenicmonomers such as styrene, alpha-methylstyrene, and vinylnaphthalene,homopolymers of ring alkyl-substituted vinylaromatic monomers such asindividual or mixed ar-methylstyrene isomers, individual or mixedar-ethylstyrene isomers, individual or mixed ar-methyl isomers ofalpha-methylstyrene, and copolymers of two or more such vinylaromaticmonomers.

f) Rubber-modified vinylaromatic polymers such as high impactpolystyrene (HIPS), and rubber-modified poly(alpha-methylstyrene), andrubber-modified copolymers of two or more styrenic monomers such asstyrene, alpha-methylstyrene, and vinylnaphthalene, rubber-modifiedhomopolymers of ring alkyl-substituted vinylaromatic monomers such asindividual or mixed ar-methylstyrene isomers, individual or mixedar-ethylstyrene isomers, individual or mixed ar-methyl isomers ofalpha-methylstyrene, and rubber-modified copolymers of two or more suchvinylaromatic monomers.

g) Alpha-olefin homopolymers such as polyethylene, polypropylene,polybutene, and copolymers of ethylene and/or propylene with one or morehigher alpha-olefins and/or diolefinic monomers.

h) Blends of at least two different thermoplastic polymers such aspolyphenylene ether/polystyrene blends, polyphenyleneether/rubber-modified polystyrene blends, and aromatic polycarbonate/ABSblends.

The amount of additive composition used in a formulation will be thatquantity needed to obtain the flame retardancy sought. It will beapparent to those skilled in the art that for all cases no singleprecise value for the proportion of the product in the formulation canbe given, since this proportion will vary with the particular flammablematerial, the presence of other additives and the degree of flameretardancy sought in any given application. Further, the proportionnecessary to achieve a given flame retardancy in a particularformulation will depend upon the shape of the article into which theformulation is to be made, for example, electrical insulation, tubingand film will each behave differently. In general, however, theformulation may contain in the range of about 5 to about 40 weightpercent, preferably in the range of about 10 to about 30 percent, of theadditive composition when it is the only flame retardant component inthe formulation.

It is especially advantageous to use the composition with an inorganiccompound, especially ferric oxide, zinc oxide, zinc borate, the oxide ofa Group V element, for example, bismuth, arsenic, phosphorus andespecially antimony, in the formulation. Of these compounds, which arewell known flame retardant synergists, antimony oxides are especiallypreferred. If such a compound is present in the formulation, thequantity of additive composition needed to achieve a givenflame-retardancy is accordingly reduced. Generally, the additivecomposition and the inorganic compound are in a weight ratio of in therange of about 1:1 to about 7:1; and preferably in the range of about2:1 to about 4:1. Formulations containing a flame retardant systemcomprised of the composition of this invention and the above inorganiccompounds may contain up to about 40 percent by weight of the system,more typically in the range of about 3 to about 30 percent by weight ofthe system, and in some applications, depending upon the flamablematerial in the formulation and the desired level of flame retardancy,preferably in the range of about 20 percent to about 30 percent byweight.

Any of the additives usually present in formulations, e.g.,plasticizers, antioxidants, fillers, (e.g., talc, glass, etc.),pigments, processing aids, UV stabilizers, and the like can be used informulation with the composition of this invention. Thermoplasticarticles formed from formulations containing a thermoplastic polymer andan additive composition of this invention can be producedconventionally, e.g., by injection molding, extrusion molding,compression molding, and the like.

The following Examples illustrates some of the features of the inventiondescribed herein and is not to be taken as limiting such invention.

EXAMPLE 1 Comparative

A 500 mL, four-necked flask was equipped with a mechanical stirrer, athermometer with a temperature regulator, a glycol-cooled(5° C.) refluxcondenser, a nitrogen flush assembly, a heating mantle and an ice-coldcaustic scrubber. The flask was charged with ethylene dibromide (250mL), containing 2.1 g of bromine(13.1 mmol), followed bydecabromodiphenylethane wet cake (product obtained directly afterfiltration in the plant, undried and unground), 5.5 g (5.66 mmol). Theslurry was stirred under nitrogen and heated to reflux (128° C.)continuously throughout the entire reaction period. The light source wasnow turned on and the entire reactor was exposed to this light to affectthe desired photobromination. The common sun lamp, using a 250 wattreflectance bulb Model 250 R 40, manufactured by GE, was used as thelight source. Within about five minutes of illumination, the reactionbegan as was evidenced from the HBr evolution, while the refluxtemperature started increasing rapidly. In the next five minutes (total10 minutes from the time illumination began), all bromine appeared tohave reacted as no red color remained and the refluxing solvent wascolorless. The light source was turned off and the reaction mixture wasallowed to cool slowly to 50° C. and then cooled in ice bath to about10° C. to precipitate most of the product. The resulting solid wasfiltered (sintered glass funnel, medium), washed with acetone to removeresidual ethylene dibromide and then dried in an oven at 100° C. for 20minutes. This gave a white, crystalline solid, weighing 4.95 g (90%).This solid had a melting point of 358-362° C. indicating it to be almostpure decabromodiphenylethane. A gas chromatograph analysis confirmedthis to be so as it showed the composition to be 0.23% DPE-Br8, 0.93area % DPE-Br9 and 98.83 area % DPE-Br10 (decabromodiphenylethane). Theethylenedibromide solvent was now analyzed by gas chromatograph-massspectrometer which showed that the solvent contained about 0.34 area %1,1,2-tribromoethane indicating that the solvent was brominatedpreferentially in this photobromination reaction.

EXAMPLE 2 Photobromination of decabromodiphenylethane toDodecabromodiphenylethane in Chlorobenzene Solvent

A 500 mL, 4-necked flask was equipped with all the desired accessoriesalmost identical to what was used in the above Example 1. The reactorwas charged with chlorobenzene(300 mL, 330 g) in which 0.7 g (4.375mmol) of bromine had been pre-weighed. Decabromodiphenylethane wet cake(10.0 g, 10.3 mmol) was now added and the slurry was stirred and heatedto reflux under nitrogen. The 0.7 g (4.375 mmol) bromine contained inthe solvent was sufficient to convert 2.1 g decabromodiphenylethane (21%of the total 10 g charged initially) completely tododecabromodiphenylethane. Since the solubility ofdecabromodiphenylethane in refluxing chlorobenzene is about 0.9 weightpercent, approximately 2.97 g of the material is expected to be insolution, which is more than required for the reaction to occur. Whenthe reflux was achieved (133° C.), the light source was turned on.Within about ten minutes of turning the light source on, the red brominecolor started fading until after about 55 minutes of reaction underillumination, all bromine appeared to have been used up as no more redcolor was seen and the slurry was pale yellow colored. The heat andlight source were both turned off and the slurry was allowed to coolslowly to about 40° C., followed by cooling in an ice bath to 15° C. Thesolid obtained after cooling was filtered through a sintered glassfunnel (medium), followed by washing with acetone to remove excesssolvent. The product was dried in air for 48 hours to give 8.24 g(82.4%) of a white solid which melted at 358-362° C. The GC analysisshowed this material to be composed of 94.2% Br10-DPE, 4.86% Br9-DPE,and a small amount (0.3%) of a product having a retention time about 2minutes longer than decabromodiphenylethane, which is deemed to bedodecabromodiphenylethane.

The chlorobenzene filtrate was now concentrated on the rotary evaporatorto give a solid residue which was slurried with acetone and thenfiltered. The residue was now dried in an oven at 100° C. for 30 minutesto give a cream-colored powder weighing 2.1 g (21%) which showed acapillary melting point of 380-386° C., which is about 20-25° C. higherthan that of decabromodiphenylethane and, therefore, is reasonable forthe higher brominated product. A differential scanning calorimetry (DSC)analysis was performed on this residue and was found to be totallydifferent from that of decabromodiphenylethane and indicative of thepresence of dodecabromodiphenylethane. Since the product had about 14%aliphatic bromine, it is expected to be more soluble thandecabromodiphenylethane in common solvents. A comparison of the thermalbehavior of the two products obtained in this run (A, recovered byfiltration from the solvent and presumed mostly decabromodiphenylethane,and B, recovered by solvent evaporation and presumed predominantlydodecabromodiphenylethane) is shown in the DSC curves given in FIG. 1.This example is given to show that the two products namelydecabromodiphenylethane and dodecabromodiphenylethane can be isolatedseparately from the same reaction, rather than as a mixture, if desired.

It is to be understood that the reactants and components referred to bychemical name or formula anywhere in the specification hereof, whetherreferred to in the singular or plural, are identified as they existprior to coming into contact with another substance referred to bychemical name or chemical type (e.g., another reactant, a solvent, adiluent, or etc.). It matters not what preliminary chemical changes,transformations and/or reactions, if any, take place in the resultingmixture or solution or reaction medium as such changes, transformationsand/or reactions are the natural result of bringing the specifiedreactants and/or components together under the conditions called forpursuant to this disclosure. Thus the reactants and other materials areidentified as reactants and components to be brought together inconnection with performing a desired chemical reaction or in forming amixture to be used in conducting a desired reaction. The fact that thesubstance, component, or ingredient may have lost its original identitythrough a chemical reaction or transformation or complex formation orassumption of some other chemical form during the course of suchcontacting, blending or mixing operations, is thus wholly immaterial foran accurate understanding and appreciation of this disclosure. Nor doesreference to a substance, component, or ingredient by chemical name orformula exclude the possibility that during the desired reaction itselfa substance, component, or ingredient becomes transformed to one or moretransitory intermediates that actually enter into or otherwiseparticipate in the reaction. In short, no representation is made or isto be inferred that the named substances, components, or ingredientsmust participate in the reaction while in their original chemicalcomposition, structure or form.

Each and every patent or other publication referred to in any portion ofthis specification is incorporated in toto into this disclosure byreference, as if fully set forth herein.

This invention is susceptible to considerable variation in its practice.Therefore the foregoing description is not intended to limit, and shouldnot be construed as limiting, the invention to the particularexemplifications presented herein above. Rather, what is intended to becovered is that subject matter disclosed herein capable of being claimedand the equivalents thereof permitted as a matter of law.

That which is claimed is:
 1. An additive mixture comprising (i) apoly(bromophenyl)alkane having in the molecule in the range of 13 to 60carbon atoms and in the range of two to four phenyl groups wherein thephenyl groups each have two or more bromine substituents, and (ii) apoly(bromophenyl)bromoalkane having in the molecule in the range of 13to 60 carbon atoms and in the range of two to four phenyl groups, saidpoly(bromophenyl)bromoalkane being in an amount which is greater than 25wt %, based on the total weight of the additive mixture.
 2. An additivemixture according to claim 1 wherein the alkane bridge of thepoly(bromophenyl)bromoalkane has at least two carbon atoms in the bridgeand at least one bromine atom substituent on the bridge.
 3. An additivemixture according to claim 1 wherein the alkane bridge of thepoly(bromophenyl)bromoalkane has at least two carbon atoms in the bridgeand at least two bromine atom substituents on the bridge.
 4. An additivemixture according to claim 1 wherein the alkane bridge of thepoly(bromophenyl)bromoalkane has at least two carbon atoms in the bridgeand a number of bromine substituents on the bridge equal to the numberof carbon atoms in the bridge.
 5. An additive mixture according to claim1 wherein the poly(bromophenyl)alkane of (i) and thepoly(bromophenyl)alkane of (ii) each have two phenyl groups.
 6. Anadditive mixture according to claim 5 wherein thepoly(bromophenyl)alkane of (i) is decabromodiphenylethane.
 7. Anadditive mixture according to claim 6 wherein thepoly(bromophenyl)bromoalkane of (ii) is dodecabromodiphenylethane.
 8. Anadditive mixture according to claim 6 wherein thepoly(bromophenyl)bromoalkane of (ii) is undecabromodiphenylethane.
 9. Anadditive mixture according to claim 6 wherein thepoly(bromophenyl)bromoalkane of (ii) is a mixture ofundecabromodiphenylethane and dodecabromodiphenylethane.
 10. An additivemixture according to claim 1 wherein the phenyl groups of thepoly(bromophenyl)alkane of (i) are perbrominated.
 11. An additivemixture according to claim 2 wherein the phenyl groups of thepoly(bromophenyl)alkane of (i) are perbrominated.
 12. An additivemixture according to claim 3 wherein the phenyl groups of thepoly(bromophenyl)alkane of (i) are perbrominated.
 13. An additivemixture according to claim 4 wherein the phenyl groups of thepoly(bromophenyl)alkane of (i) are perbrominated.
 14. An additivemixture according to claim 5 wherein the phenyl groups of thepoly(bromophenyl)alkane of (i) are perbrominated.
 15. An additivemixture according to claim 5 wherein the poly(bromophenyl)alkane of (i)is docabromodiphenylmethane.
 16. An additive mixture according to claim5 wherein the poly(bromophenyl)bromoalkane is dodecabromodiphenylethane.17. An additive mixture according to claim 5 wherein thepoly(bromophenyl)bromoalkane is undecabromodiphenylmethane.
 18. Anadditive mixture according to claim 12 wherein thepoly(bromophenyl)bromoalkane is dodecabromodiphenylethane.
 19. Anadditive mixture according to claim 15 wherein thepoly(bromophenyl)bromoalkane is undecabromodiphenylmethane.
 20. Anadditive mixture according to claim 14 wherein thepoly(bromophenyl)bromoalkane is undecabromodiphenylmethane.